1. Field of the Invention
The invention relates to a device for catching a subterranean well pump and a portion of the tubing string carrying said pump.
2. Description of the Prior Art
During production of subterranean wells, a submersible electric pump is sometimes attached to the bottom of a production tubing string within the well casing, or other conduit, at depths typically of several thousand feet. Despite precautions, the tubing string carrying the pump may eventually break, due to corrosion, an accident during a retrieval operation, or the like. In such a case, the pump, the lower portion of the tubing string, broken electric cables, and bands which normally retain the cables, may drop to the bottom of the well. The resultant buckling of the tubing, and tangle of cables and bands makes a fishing retrieval operation extremely difficult. Additionally, a drop of any significant distance may, of course, damage or destroy the pump.
To limit the fall distance of a pump in such an accident, it has previously been attempted to first anchor a separate drillable cement retainer or drillable packer to the well casing, below the depth to which the pump would then be run. While a retainer or packer tool so anchored may be able to stop the fall of a pump, such a makeshift arrangement has required an additional setting operation.
Because setting of a device to catch the pump by means of tubular rotation is an unacceptable method for most operators, due to interference with electric cable running down the exterior of the tubing, a pump catcher must also be reliably set and released only by controlled longitudinal movement of the tubing string.